#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pii = pair<int, int>;
#define rep(i, a, b) for (int i = (a); i <= (b); i++)
#define per(i, a, b) for (int i = (a); i >= (b); i--)
#define endl '\n'
const int N = 2e5 + 5;

int n, m;
int a[N];

int main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  int t;
  cin >> t;
  while (t--) {
    int x;
    cin >> x;
    if (__builtin_popcount(x) == 1 || __builtin_popcount(x + 1) == 1) {
      cout << -1 << endl;
      continue;
    }
    int y = 3;
    while (true) {
      int z = x ^ y;
      if (y > abs(x - z))
        break;
      else
        y <<= 1;
    }
    cout << y << endl;
  }
  return 0;
}